Electron beam lithography at 10keV using an epoxy based high resolution negative resist (original) (raw)
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An advanced epoxy novolac resist for fast high‐resolution electron‐beam lithography
Aspects of the formulation of a highly sensitive cresol epoxy novolac-based chemically amplified negative resist ͑epoxy resist, EPR͒ and optimization of critical process parameters for high-resolution electron-beam lithography are reported. The bulk resist sensitivity ͑E 80 , dose for 80% thickness retention͒ is 0.9 C cm Ϫ2 at 40 kV. The effect of postapply bake and postexposure bake on resist sensitivity, contrast, and resolution are investigated and optimized for lithography up to the 0.1 m regime. The resist process is characterized by a good exposure dose latitude and relevant insensitivity to the variation of thermal processing conditions. Postexposure bake temperature variations in the 90-130°C range cause minimal change in sensitivity but remarkable change in contrast. Due to this behavior the resist process is not described satisfactorily by the reaction kinetic models commonly used to characterize chemically amplified resists of different chemistry.
Microelectronic Engineering, 1994
In this article we present results of Electron-Beam Lithographic (EBL) and Reactive ion Etching (RIE) experiments on a single layer chemically amplified novolak-based negative &Qmponent resist System (3CS). The resist type used was AZ PN114 from HOECHST AG. Direct, shaped-EBL generated single-layer resistrelief structures at O,lpm and below were RIE and RIE with magnetic enhancement transferred (i) into bulk silicon and GaAs substrates and (ii) in 400 nm Nblayer on SiO,/Si.
Polystyrene negative resist for high-resolution electron beam lithography
Nanoscale Research Letters, 2011
We studied the exposure behavior of low molecular weight polystyrene as a negative tone electron beam lithography (EBL) resist, with the goal of finding the ultimate achievable resolution. It demonstrated fairly welldefined patterning of a 20-nm period line array and a 15-nm period dot array, which are the densest patterns ever achieved using organic EBL resists. Such dense patterns can be achieved both at 20 and 5 keV beam energies using different developers. In addition to its ultra-high resolution capability, polystyrene is a simple and low-cost resist with easy process control and practically unlimited shelf life. It is also considerably more resistant to dry etching than PMMA. With a low sensitivity, it would find applications where negative resist is desired and throughput is not a major concern.
Aqueous base developable epoxy resist for high sensitivity electron beam lithography
2000
Aqueous base developable, chemically amplified negative resists, based on epoxy chemistry are introduced and evaluated for high resolution, high speed e-beam lithography. These resists are formulated using partially hydrogenated poly(hydroxy styrene) and epoxy novolac polymers and they do not suffer from thermal instability of unexposed regions during processing. Degree of hydrogenation controls the aqueous base solubility and micro phase separation phenomena. Reduction of edge roughness compared to the pure epoxy systems is observed whereas the absence of swelling phenomena allows lithography up to 100 nm regime.
44th International Conference on Electron Ion and Photon Beam Technology and Nanofabrication (EIPBN), 2000
A new aqueous base developable, chemically amplified negative resist based on epoxy chemistry is evaluated for high-resolution, high-speed e-beam lithography. This resist is formulated using partially hydrogenated poly͑hydroxy styrene͒ and epoxy novolac polymers. Degree of hydrogenation controls the aqueous base solubility and microphase separation phenomena. Reduction of edge roughness compared to the pure epoxy systems is observed whereas the absence of swelling phenomena allows lithography up to 100 nm regime and a sensitivity of 4-8 C/cm 2 at 50 keV. The diffusion coefficient has been evaluated both from high-resolution line and dot exposures and it is found to be 5ϫ10 Ϫ14 cm 2 /s for the optimal thermal processing conditions selected.
Electron beam lithography: resolution limits and applications
Applied Surface Science, 2000
. We report on the resolution limits of Electron Beam Lithography EBL in the conventional polymethylmethacrylate Ž . PMMA organic resist. We show that resolution can be pushed below 10 nm for isolated features and how dense arrays of periodic structures can be fabricated at a pitch of 30 nm, leading to a density close to 700 Gbitrin 2 . We show that intrinsic resolution of the writing in the resist is as small as 3 to 5 nm at high incident electron energy, and that practical resolution is limited by the development of the resist after exposure and by pattern transfer. We present the results of our optimized process for reproducible fabrication of sub-10 nm lines by lift-off and 30-nm pitch pillar arrays by lift-off and reactive ion Ž . etching RIE . We also present some applications of these nanostructures for the fabrication of very high density molds for Ž . nano-imprint lithography NIL and for the fabrication of Multiple Tunnel Junction devices that can be used for single electron device applications or for the connection of small molecules. q 2000 Published by Elsevier Science B.V.
SPIE Proceedings, 2016
In this contribution, we present the results of a systematic material variation for the development of a resist material for high resolution positive tone electron beam lithography (EBL). Several acrylic copolymer materials with different compositions, that is varying mass fractions of the comonomers and different molecular weights, were synthesized andas resist solutions-evaluated in terms of EBL performance at acceleration voltages of 30 kV and 100 kV. The resist material exhibiting the best combination of the desired properties, named mr-PosEBR, is two times more sensitive than PMMA 495k and performs comparably to the known high resolution resist ZEP520A at 30 kV. For example, a grating pattern with 29 nm wide lines with a period of 100 nm could be lithographically generated in films of mr-PosEBR with an area dose of 100 µC/cm 2. In terms of resolution, single lines of only 35 nm width could be fabricated via metal liftoff. Furthermore, the dry etch stability of mr-PosEBR in a CF 4 /SF 6 process is similar to the one of ZEP520A. Consequently, via dry etching nano patterns in mr-PosEBR could be smoothly transferred into the underlying Si substrate with high fidelity. Moreover, mr-PosEBR was evaluated as electron beam grayscale patterning and reflow resist. It was shown that the resist exhibits a good grayscale and reflow performance very similar to PMMA 120k and ZEP520A. Via these well controllable processes the generation of a wide variety of features and applications is possible.
Electron beam lithography using chemically-amplified resist: Resolution and profile control
Microelectronic Engineering, 1996
The effect of post exposure bake and softbake conditions on the sensitivity of AZPN114 has been investigated experimentally. A bilayer system for undercut structures has been achieved using two layers of AZPN114 with different softbake temperatures. A single layer of AZPN1 i4 has also been used to produce undercut and tailored resist profffles by two different multiple exposure strategies at different beam energies.
A new nanocomposite resist for low and high voltage electron beam lithography
Microelectronic Engineering, 2003
A novel nanocomposite photoresist was synthesized and characterized for use in both low and high voltage electron beam lithography. This resist system is shown to display the ideal combination of both enhanced etch resistance and enhanced sensitivity required to satisfy both low and high voltage patterning applications. Resist sensitivity was enhanced by the direct incorporation of a photoacid generating monomer into the resist polymer backbone while the etch resistance of the material was improved by copolymerization with a POSS containing monomer.